1. Field of the Invention
The present invention relates to various covers for use in connection with an engine and methods for producing the same, and more particularly to the covers which are formed of new material to improve the noise reduction thereof.
2. Description of the Prior Art
As various covers for use in connection with an internal combustion engine, there are, for example, rocker covers (cylinder head covers), front covers, dust covers, undercovers, engine air filter casings and their covers, noise reducing covers located in the vicinity of the outer surface of the engine, oil pans to be filled with engine lubricating oil, and hood-insulators.
Heretofore, these covers have been formed of sheet metal or plastics and therefore tend to easily transmit vibration therethrough. As a result, these covers are excited to vibrate by the vibrations due to engine running and due to intake air pulsation. This causes, for example, the air filter or the dust cover to generate sound, thereby increasing engine noise.